1. Field of the Invention
The present invention relates to a method to join two elements, and a joint made according to the method.
2. Description of the Prior Art
For numerous applications, it is desired to join two elements, one of the elements being located surrounding the second element. Such a joint can be used for attachment purposes, or to join together two elements, in the latter case either by the use of a separate surrounding member, e.g. a tubular member located surrounding the end portions of two pipes, or two members, one having a larger internal diameter than the outside diameter of a second member, the first member arranged surrounding the second member. A joint can be accomplished by means of welding, provided that the distance between the adjacently located surfaces of the elements is rather small. However, since welding is a rather time-consuming method to accomplish a joint, and since welding also requires skilled personnel, other methods to accomplish a joint have been proposed. With regard to the method and the joint according to the present invention, the most relevant prior art is disclosed in Norwegian Patent Specification Nos. 136.223 and 141.128, which disclose a joint accomplished by the use of one, or a number of explosive charges, arranged to cause expansion of a surrounding tubular member, thereby forming a frictional joint between two elements. However, the prior art as disclosed in the above two patents only facilitates accomplishment of a joint in a minimum of time, but the joint lacks certain desired features, since it requires that one of the elements is specifically arranged to hold the expandable tubular joint, and since it only accomplishes a joint of frictional type, without any sealing elements.